mmc: rtsx: Let MMC core handle runtime PM

mmc: rtsx: Let MMC core handle runtime PM

Since MMC core handles runtime PM reference counting, we can avoid doing
redundant runtime PM work in the driver. That means the only thing
commit 5b4258f6721f ("misc: rtsx: rts5249 support runtime PM") misses is
to always enable runtime PM, to let its parent driver enable ASPM in the
runtime idle routine.

Fixes: 7499b529d97f ("mmc: rtsx: Use pm_runtime_{get,put}() to handle runtime PM")
Reviewed-by: Ulf Hansson <ulf.hansson@linaro.org>
Signed-off-by: Kai-Heng Feng <kai.heng.feng@canonical.com>
Link: https://lore.kernel.org/r/20220216055435.2335297-1-kai.heng.feng@canonical.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>